1. Field of the Invention
This invention relates to a charging method and device, more particularly to a relatively efficient charging method and device.
2. Description of the Related Art
As illustrated in FIG. 1, a conventional charging device (not shown) first charges a battery (not shown) in a constant current mode (CC mode). In the CC mode, the conventional charging device charges the battery with a first charging voltage (V1) and a first charging current (C1). The first charging voltage (V1) has a value that is increasing, while the first charging current (C1) has a value that is constant, i.e., 1320 mA. When the conventional charging device determines that the value of the first charging voltage (V1) is equal to a normal charging voltage value of the battery, i.e., 4200 mV, the conventional charging device then charges the battery in a constant voltage (CV mode). In the CV mode, the conventional charging device charges the battery with a second charging voltage (V2) and a second charging current (C2). The second charging voltage (V2) has a value that is equal to the normal charging voltage value of the battery, while the second charging current (C2) has a value that is decreasing.
Although the aforementioned conventional charging device achieves its intended purpose, the conventional charging device is relatively inefficient.